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COMPARISON OF ANALYSIS MODELS OF HIGHWAY AND RAILWAY BRIDGES--LOADS AND LOAD COMBINATIONShttp://etd.aau.edu.et:80/dspace/handle/123456789/4930
Title: COMPARISON OF ANALYSIS MODELS OF HIGHWAY AND RAILWAY BRIDGES--LOADS AND LOAD COMBINATIONS
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<br/>Authors: Nuruye, Adane
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<br/>Abstract: Ethiopian engineers have good experience of highway bridge design. Currently railway bridges are necessary due to new railroad route projects in Ethiopia. It is absolutely necessary to bring the well developed knowledge of the engineers on Highway Bridge to Railway Bridge engineering because Railway Bridge needs careful design and detailing.
The work presented in this thesis compares the loading model and load combinations of Highway Bridge and railway bridges. Fatigue loads, serviceability requirements, their respective design philosophy, and related topics are briefly presented. Simply supported two lanes Highway Bridge (LRFD Method) and a double track Railway Bridge (ASD Method) of 30m span each are used as design examples. The design examples are neither complete nor optimum. The main sources of these loading conditions are AASHTO LRFD Specification and AREMA MRE 2010. Beside these codes, various theories and design books, thesis works, and journals on both types of bridges are used to enrich as well as disclose clearly the fundamental codes’ intention, explanatory figures and diagrams.
The comparison mainly focuses on loads for fixed bridges, such loads as live load, centrifugal force, lateral force due to wind load, longitudinal force and impact.PREDICTION OF SOIL WATER CHARACTERISTIC CURVE BASED ON GSD AND PI FOR RED CLAY AND EXPANSIVE SOILS FOUND IN ADDIS ABABAhttp://etd.aau.edu.et:80/dspace/handle/123456789/4929
Title: PREDICTION OF SOIL WATER CHARACTERISTIC CURVE BASED ON GSD AND PI FOR RED CLAY AND EXPANSIVE SOILS FOUND IN ADDIS ABABA
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<br/>Authors: NURU, ISMAIL
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<br/>Abstract: Many researchers have done researches on unsaturated soil mechanics worldwide to bring the
unsaturated soil mechanics in to practices. Among those researches some of them focused on
simplifying the complex and expensive testing mechanism by developing models which can be
used to predict the unsaturated soil parameters from basic soil prosperities such as Grain Size
Distribution (GSD) and Plasticity Index (PI) along with the saturated shear strength parameters.
Soil water characteristic curve (SWCC) was proved to have good relationship with the
unsaturated soil parameters. In this study an attempt was made to check whether those developed
models would work for expansive and red clay soils found in Addis Ababa.
Using the model developed by Fredlund and Xing (1994) along with the correlation equation
given by Perera et.al (2005), family of SWCC for soils found in Addis Ababa has been plotted. It
was observed that the family of SWCC plotted was out of the widely referenced family of curves
developed by Zapata et.al (2000) to some extent. Even though the family of curves seems to be
out of the range provided by Zapata et.al (2000), the model gave good prediction for the
unsaturated shear strength parameter Φb.
The percentage error between the measured values of unsaturated shear strength parameter Φb in
previous researches of Habtom (2010) and Getaneh (2010) with predicted unsaturated shear
strength parameter Φb in this study was compared.
For red clay samples the percentage error lie in the range 2.07 to 6.37% for suction ranges of
36.67 to 52.9 kPa and at lower suctions of 16.75 and 21.5 kPa the percentage error ranges from
11.42 to 25.39% .
For expansive soil samples for suction of 23.1 and 32.9 kPa, the percentage error is in the range
from 3.86 to 6.13%. For suction values of 14.5 and 52 kPa the range of error is about 9.45 to
13.40% and for suctions of 38.8 and 48.6 kPa the error lies between 18.94 and 38.84%.Ensuring Functional Sustainability of Water and Sanitation Developments in Rural Areashttp://etd.aau.edu.et:80/dspace/handle/123456789/4928
Title: Ensuring Functional Sustainability of Water and Sanitation Developments in Rural Areas
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<br/>Authors: Fiseha, Israel
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<br/>Abstract: Ensuring functional sustainability of water and sanitation developments throughout the design period is
vitally necessary. It helps to identify the main causes of non functionality and indicate the troubleshooting
for non functionality per scheme system components at the stage of design, construction and service
period.
To identify the major causes of non functionality the research has employed both primary and secondary
data sources. Secondary data was collected from respective governmental and non-governmental
organization at federal, state and woreda level. Primary data, on the other hand, was obtained using
questionnaire, Focus group Discussion (FGD) and observation.
Data from the secondary and primary sources enabled the researcher to scan and investigate more than 95
% of water and sanitation schemes in Chencha woreda rural areas. The common rural water and sanitation
technologies include hand dug well, shallow well, spring with gravity distribution, spring at spot and
simple pit latrine. All have been studied and evaluated for their cause of non functionality.
The research found that 87 % of non functionality occurred before its estimated design period, which is
within ten years. But the average non functionality occurrence of the schemes is between six years up to
seven years. The most common non functionality causes are poor design, below the standard construction
and poor institutional set ups of water and sanitation infrastructures. It includes: spring capping failure,
management and financial problems, construction materials problems, source yield decreasing, poor
quality of water, pumping system failure, poor quantity of water and pipe line failures.
Water and sanitary schemes are functionally sustainable, only when social, financial, technical,
institutional and environmental factors are integrated with every project life stages. The stages are needs
assessment, conceptual design, design and action planning, implementation, and operation and
maintenance. To get rid of non functionality every system component design and construction activity
should be in accordance with the applicable design and construction methods.
All respective governmental, nongovernmental and community stakeholders should carry out
responsibility for functionality and sustainability of water and sanitation schemes. It is impossible to meet
the functionality of water and sanitation schemes developments, without the integration of all respective
bodies in all project life stages through feasibility study, designing, construction and service periodsStudy some of the Engineering properties of soil found in Asela Townhttp://etd.aau.edu.et:80/dspace/handle/123456789/4927
Title: Study some of the Engineering properties of soil found in Asela Town
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<br/>Authors: Belayhun, Yilma
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<br/>Abstract: The aim of this thesis is to provide in-depth engineering properties of Asela soils. Asela is the capital of Arsi zone, which is developing rapidly. Rapid urbanization in the city area has led to an increased interest in the engineering behavior of the soils which are present within the city area. Geotechnical information of the subsoil in an urban area is important for various civil engineering works. Non-availability of the proper geotechnical information of the subsoil makes foundation and engineering works expensive, difficult and sometimes hazardous.
A total of 20 bulk samples were taken, batched into two and subjected to Air and Oven drying. Thereafter, engineering properties such as moisture content, sieve analysis, Atterberg limits, specific gravity, free swell, unconfined compression test and one dimensional consolidation characteristics of the soil were evaluated. Based on visual observation, indicative tests and geochemical test results the soil of the study area is dominantly covered with laterite and lateritic soil which is mainly used as construction material.
The study has shown that index property values are sensitive to pre-treatment of the samples prior to testing, particularly to pre-drying, for Atterberg limit, specific gravity and particle size determination tests, to the degree of manipulation or mixing of the test sample. Pre-drying of any sort leads to false and inconsistent results and it is recommended that tropical red clays are always tested from their field moist state with no pre-drying.
The research includes the study of shear strength of undisturbed soil compare to remolded sample using unconfined compression test. The shear strength of the selected soil was studied through their stress- strain was drawn for obtaining the un-drained shear strength properties. The results indicate that the undisturbed samples performed better than remolded samples with higher shear strength.